Alterations of redox states in primary CLL cells. (A) Increase of basal ROS in primary CLL cells, detected by flow cytometry using 1 μM DCF-DA. Representative histograms for CLL cells and normal lymphocytes are shown. (B) Quantitative comparison of the basal ROS levels between normal lymphocytes and primary CLL cells from 12 healthy donors and 33 CLL patients. Each bar represents the mean and 95% CI. (C) Decrease of basal reduced and oxidized glutathione (GSH and GSSG) in primary CLL cells (n = 9), compared with that of normal lymphocytes (n = 5). Each bar represents the mean and 95% CI. (D) GPX enzyme activities of normal lymphocytes (n = 4) and primary CLL cells (n = 8). Each bar represents the mean and 95% CI. (E) Basal expression levels of glutathione synthesis enzyme GCS (GSH1) in lymphocytes from 3 healthy donors and 3 CLL patient samples. (F) Correlation between the IC₅₀ values of PEITC (MTT assay) and the basal ROS levels in primary CLL cells (n = 18). Spearman correlation coefficient r = −0.872, P < .001. (G) Lack of correlation between the IC₅₀ values of F-ara-A (MTT assay) and basal ROS levels in primary CLL cells (n = 21). Spearman correlation coefficient r = −0.368, P = .100.